Re: [Phys-l] Climate skeptic convinced by data. Was: Re: Mike Mann _The hockey

[Spinozalens@aol.com]

The only reasonable uncertainty in climate science  is in  predicting the 
consequences of the very large increase we are certain has  occurred in green 
house gasses. That we have warming and that's it's  related , , at least to 
a large part , to Human activity is not much in doubt.  It's my 
understanding that the climate models are proving to have been too  optimistic, due to 
previously unidentified positive feed back mechanism. Glacier  retreat and 
global temperature rise  are higher then  the models  predicted. However, we 
need longer term observation to rule out temporary  fluctuations. Even more 
troubling is the potential for large scale methane  release from warming 
Arctic permafrost which wasn't considered, as far as I  know,  in the original 
UN sponsored climate study. It's just crazy to not  move in a careful 
prudent way to non or lower  green house emission energy  sources , if we are 
wrong about the effects we still get the good effects of  more secure and 
cleaner energy technology , if we are right and do nothing, that  is  we continue 
to accelerate the use of fossil fuels, it may well  lead to a Human disaster.
 
Bob Zannelli      
 
 
))))))))))))))))))
 
 
In a message dated 2/19/2012 10:26:18 A.M. Eastern Standard Time,  
bblais@bryant.edu writes:

On Feb  18, 2012, at 17:12 PM, John Denker wrote:

> 2) There is no serious  doubt that atmospheric CO2 has recently increased.
>
> 3) There  is no serious doubt that the increase in CO2 is anthropogenic.
> The  isotope signature gives it away.

I'm ok with these (2) and  (3).  


> 1) There is no serious doubt that the recent  increase in temperature is 
> unprecedented over the last 1000 or 2000  years.

this part (1) is where I disagree.  How do we know that it  is 
unprecedented in the past 1000-2000 years?  from proxy data.   From everything I have 
seen, there is serious doubt on this, on several  grounds:

a) there is a systematic downplaying of the  uncertainties.  I've looked at 
the data myself, and have found the  variability to be startlingly high.

b) the methods that are made to  downplay the uncertainties seem to be both 
sensitive to a very small subset of  the proxy data set, and also seem to 
pick out "hockey-stick" shapes out of  noise.  combined with a general lack 
of openness with the data and  methods, this calls into question the 
confidence in the analysis

c) we  know that some of the proxy reconstructions predict *opposite* 
trends for 1/3  of the time period where we *know* the actual temperature.  this  
divergence problem, which may perhaps have a reasonably solution, call into 
 question the validity of the reconstructions during the times where we 
don't  have independent confirmation.

d) the models are tuned to this  temperature profile.  so, if the proxy 
data are wrong, or the temperature  reconstructions from them are wrong, then 
the models will be wrong.  It  won't matter if all the models agree, or that 
they agree with the proxy data  (to which they are tuned). 

e) there is at least some evidence that it  was warmer at some point during 
the last 2000 years, which would certainly  call into question all of the 
claims.  I am not saying I am necessarily  convinced by this evidence 
entirely, but with the stakes as high as they are,  this needs to be handled very 
carefully.

> 4) There is no  serious doubt that item (3) explains item (2). Since item 
(2)
> in turn  explains item (1), this means that the warming is anthropogenic.

well,  actually it is not true that your item (2) necessarily explains your 
item (1):  it depends on the feedbacks in the system, which are only now 
being measured  independently.  If, for example, there are strong negative 
feedbacks in  the system then (2) won't lead to (1).  Are we confident in our  
understanding of these feedbacks? not even close.

Although I think it  is *plausible* that we are causing at least *some* of 
the warming observed, I  am not convinced that we are responsible for *all* 
of it (although that is  possible) and I am not confident that it is 
unprecedented in the past 2000  years.  I definitely don't trust the proxy data, 
and thus the models  (garbage in = garbage out).  I'd love to be convinced 
otherwise, but I  haven't seen this addressed well in the climate community.  
The  "Climategate" emails, and the descriptions written over at 
climateaudit.org,  seem to indicate a tendency to tribalism and closed procedures in the 
climate  community, and to Michael Mann's group in particular.  I like Dr 
Muller's  Berkeley Earth Surface Temperature project...the same needs to be 
done for  proxy data, so everything is out on the table.  Perhaps when we have 
an  open process we can actually determine the truth from the fiction.

I  think the attitude of "global warming is a settled issue" is contrary to 
 science, and to the obvious uncertainties that even a cursory look at the  
actual data shows.


bb

-- 
Brian  Blais
bblais@bryant.edu
http://web.bryant.edu/~bblais
http://brianblais.wordpress.com/




_______________________________________________
Forum  for Physics  Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l